1. Field of the Invention
The invention relates to an arrangement of at least two cables which extend adjacently in a substantially parallel manner, a first cable and a second cable of which each having at least one stranding group which has two or more conductors that are twisted together.
2. Description of Related Art
A twisting or stranding is generally understood to mean the twisting around each other in a helical manner of several wires or conductors of a cable. For example, a known twisted-pair cable has at least one stranding group which comprises two conductors which are twisted around one another. The individual conductors thereby change places in the longitudinal direction of the cable. In addition, twisted or stranded wire pairs offer better protection against external alternating electromagnetic fields and electrostatic interference.
A crosstalk between several conductor pairs running adjacent to one another in a cable can also be effectively reduced through stranding. In addition, differing lay lengths and/or directions of rotation of the individual stranding groups of a cable can be chosen. An external signal from a first conductor pair can be coupled into an adjacent second conductor pair inductively or capacitively.
Such undesired crosstalk between the cables (alien crosstalk) can also occur if several cables which each have at least one conductor pair for the transmission of differential signals are laid adjacent to one another. In order to reduce this crosstalk, the individual cables are regularly provided with a shielding. Alternatively, coaxial cables are used.
In other known solutions, the individual cables laid adjacent to one another have a particularly thick sheath or are laid at a predetermined minimum distance from one another.
The document US 2012/0186846 describes arranging several stranding groups in a cable, whereby the stranding groups can in turn be twisted together. The lay lengths of the individual strandings can vary. However, the manufacture of such a cable is particularly complex. Also, alien crosstalk can occur between several such cables which are laid adjacent to one another.
The document EP 2131 370 B1 also describes stranding two stranding groups together with one another, whereby the lay length of the group stranding varies sinusoidally. This cable too is complex to manufacture. Also, alien crosstalk can occur between several such cables which are laid adjacent to one another.
The lay length is understood to mean the pitch or turn distance of the helix traced by the stranding group. In other words, the lay length is the distance over which one of the stranded wires of a stranding group twists during a complete rotation in the longitudinal direction of the cable (z-direction).